The present invention relates to electronic communications, and more specifically concerns transferring data by either wired or wireless means between a computer and a telephone system or similar communications facility.
Many desktop and portable computers interface with the public switched telephone system or similar communications network via a data converter such as a modem. Typically, the connections to such systems or networks are physically implemented as a plug located at a fixed position on a wall. A physical wire or cable then connects this jack to a connector on the modem, and the modem is plugged into a slot in the computer. Other types of fixed-position connectors include floor-mounted receptacles, short cable stubs running through heating and ventilating ducts, and connector blocks tapping into loose cables running through ceiling panels, along baseboards, and through office cubicles.
Most office-based or home-based desktop personal computers attach to a communications network by a wired connection to a modem implemented as a small card or package mounted inside or alongside the computer. This type of attachment is inexpensive and adequate as long as the computer remains in a relatively fixed position convenient to a fixed-position network plug.
However, sometimes a wired connection between a computer and a communications network is inconvenient or not feasible, even when the computer remains only a short distance from the fixed plug. For example, a person may wish to handle e-mail from a laptop personal computer at a table across the room from the nearest telephone plug. A wire snaked across the floor is a tether against mobility, as well as an invitation to damage to the computer. Many other situations would also welcome a way to allow short-range mobility of a computer or other data processor while remaining connected to a telephone or other form of network.
Wireless modems and other interfaces are known in the art. Infrared links between laptops and printers are becoming common. Radio-frequency systems are beginning to assert themselves. However, wireless links of all kinds suffer from several disadvantages. First, they tend to be more expensive than their hard-wired equivalents. If everyone in a building or office complex required relatively wide-range mobility, conventional wireless systems might prove economical. But frequently only a small number of people in an office need mobility, and then only over short distances. Neighborhood and building wireless systems for residential and hotel use are not yet widely available, and they promise to require expensive equipment.
In any event, many users desire both wired and wireless capability. Even if wireless components become plentiful and cheap, users must purchase both wired and wireless equipment offering essentially the same functionality. This duplication of functionality greatly increases the cost of communication. Moreover, modems tend to become obsolete quickly, as speeds and features improve. Keeping up then requires additional purchases of both types of gear, even though the wireless-interface transceivers in a link tends to change less rapidly. For example, the infrared portions of a TV remote control and the radio-frequency chips of a cellular telephone operate at essentially the same parameter values that they did ten years ago; they have merely become less expensive. Moreover, the conventional conversion of modulated digital data directly to radio-frequency format raises technical problems; it is not presently clear, for example, that modem protocols operating at 56 Kbps or higher speeds will perform satisfactorily with wireless transceivers.
Accordingly, many "wired" computer users would welcome an individual, short-range, inexpensive, easily upgradable wireless interface to a communications system.